Method of charging secondary batteries.



. M; R. HUTCHISON.

METHOD OP CHARGING SECONDARY BATTERIES. APPLICATION FILED JULY 1911.

1,117,493. Patented N0v.17,1914.

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APPLIGATION FILED JULYG, 1911.

l ,l 17,493. Patented Nov` 1*?, 1914L 2 SHEETS Y SHEET Z.

UNrrED y sTATEsPA'rENT OFFICE.

MILLER REESE HU'.[CIl'.IS()N,` OF WEST ORANGE, NEW JERSEY, ASSIGNOR T0 EDISON STORAGE BATTERY COMPANY, OF WEST ORANGE, NEW JERSEY, A CORPORATION METHOD OF CHARGING SECONDARY BATTERIES.

Specification of Letters Patent.

Patented Nov. 17, 1914.

Application led July 6, 1811. Serial No. 63?;177.

To all whom it may `concern Be it known that I, MILLER HUTCH! IsoN, aitizen of thev UnitedA States, and a residentof fest Orange, county of Essex, and State of New' Jersey, have invented certain new and useful Improvements in Meth? ods `of Charging lSecondary Batteries, of which the following is a description.

My -invention relates to a method of charging secondary batteries and to the cir cuits by which the cells of a battery may be connected during the carrying out of my improved method.

The objectof my invention Vis to provide a simple and expeditious method of charging. thgl cells of. a. secondary battery under condi'tins which render it impossible to charge-the batteryivith all of the cells i thereof connected together 'in series.

My invention is equally applicable to battei-ies of the lead or acid type or the alkaline type, but the Edison type of alkaline storage battery u'ill be particularly referred to for purposes of illustration inthe specification.

When the operation of charging a cell of an Edison type battery 'is completed or nearly completedthe P. D. around the terminals of the cell is about 1.8 volts. The average/E. M. F. of such a cell on normal discharge is 1.2 volts, and on heavy discharge the average is between l volt and 1 .1 volts. In the case of the lead type of balttery also, the P. D. on charge is greater than the electromotive force of the battery' on discharge. In many instances Where a definite number of cells must be used to give the 'voltage vrequired on discharge, the P. D.

around the terminals 'of' the battery, if all were connectedtogether in series for charging, would be greater than the maximum voltage of the source which happensto be available. My improved method is designed to overcome this ditiic'ulty; and generally speaking, contemplatesdividing the'rbattery into groups of cells, connecting together a plurality of these groups in such a manner and charging to part capacity, and continuingthe operation u ntilall of the cells have been fully charged, fully charged groups of cells being omitted when new connections are made. the division of the groups and the length of charge given being so calculated preferably that all ofl the divisions of connected groups of cells contain the same number of groups and the partial charges given may all be equal.

ln order that my invention may be more clearly understood attention is hereby directed to the accompanying draiving's forming part of this specification and illustrating liagrammatically arrangements'of dividing the cells and connecting' the same according to myimproved nicthod. ,l

In the drawings, Figures 1, Q and 3 represent successive wiring connections for cl'iarging a battery which is divided into three groups of cells; Fig. 4' represents the battery connected for discharge; Figs: 5 and 6 represent successive wiring'- connections fo'r chargingthe battery lwhen one group of cells thereof is more fully charged than the others before the connections are made: Figs. 7, 8, 9 and 10 represent successive wiring connections for charginga battery which is divided into four vgroups of cells; vand Figs. 11. 12, 13, 14 and 15 repre sent successive wirihg connections for charging a battery which is divided intol tive .groups of cells.

F or illustration of the me'thod practised as illustrated particularly by Figs. l, 2, 3 and 4, I vvill assume a battery of 210 cells installed on al floating crane, which battery, on the one hour discharge rate, shows an average voltage of 220. I also'lassu'me that the circuit for charging the cells is connected'to a commercial type of-compound wound generator. capable of supplying a maximumof 252 volts, and also that the cells are to be used to operate the 220 volt motors of the hoisting cranes. In order to charge these 210 cells connected together in series, I would certainly have to connect them to a line carrying at least 378 volts, whereas 252 volts is the maximum available. Accordingly, the supply mains being represented diagrammatically in' the'drawmgs by 1 'and 2, I divide the battery intothree parts, each containing 70 cellsand designated in the'drawiiigs". A, B and C, respec tively. The groups A, B and-C are repre-'- sented diagram'matically as .having yterminals 3 4, 5-6, 'and 7 8, respectively. To charge, -1 first"c'onnect twol of the groups as for example, A and B, in'series and connect 'cross the 252 volts mains 1 and 2. This is .illustrated in Fig. I infxvhich termiv nals Itand 5 of groups .A and B, are connect'ed together by conductor 9 and-thc terminals 3 and 6 are connected to the mains by conductors 1.0 und 11. This gives a :mxmuxn P. D around the terminals of -A and B of-252 volts and accordingly no external resistance need be includedin'the connections. Groups A and B are left con# nccted tothe mains until they are both half charged, Then one f the groups, :is for example.f\,.1s`dzsconnected, and groups B und C ancconnected in series and acro the mains, asjillustrated .in Fig. 2, in which termmalS-,G nd'are connected by condoctor 12 and terminals 5 and 8 arc-com nectcd .to the-mains ,l and 2, respectively. 'llnsconnection lsleft-standing until group B becomesiully.charged and group C be comes half clim-ged. A Group B is then disconnected sind group A substituted there-I for, 'the-terminals Lend 7. of groups A and B being connectedtogether and terminals 3 and 8 of groups A `and@ being connected to the ni'aiiis icspectively, as shown in Fig;

3. Groups A and C arefnow half charged.

and remain connected gto. the mains until they aref fully` clmrgjred,` the whole battery now being 'fully7 charged, and ready for a series connection-to deliver 220 volts. T his connection for discharge is illustrated in Fig. 4 in which groups A, B and C are .connected togetherin series shown, and connected to theI mains, which thev supply with :22A v"oltcurrent.

In the event of the machinery of the' crane being used when it is at a dock it may boo desired to "float" cells on theQSfO voltI line on the slur-neto boost the lineA when the voltage thereoi` drops because of heavy load. ln si'ich' a case any two of the groups A. B and C maybe connected in series and IIC-ross. theline` :is the Edison cell floats at 1,53 volts, neither taking norgiving energy when fully charged and connected 'to e circuit of volts. il@ cells connected in .series give 214.2 volts, when euch cell has o voltage of 1.53, and the 220 volt line will drop to this zeltzfrfgc on hez-.v f=lon d. Some current willbelaken by vthe cells so connected on a 922i) volt line. but when the voltage drops'belon" (lil v olts thc cells vvill discharge und. thus; mostf Athe linev ln the event' ojffor example. gronpsrl. and B becoming" completely discharged lor more fullydisclwreed than group C dur-V ing.: the process otboostingthe battery can tlien be'l easily charged bythe connections '.l` Cf and D, of ivhichanythreecanbe'ednnected together 'in 'seriesfand 'charged1 with' are to lund E.

shown-in F fandfG. ItV beih stood thatgroups A and Bare more fully discharged than group.C,.groups A and fB;

. fully charged, InFig. 6 terminals l and 1' 5 of groups and B are connected .together l' A and terminals nnd'' of'groups;\'. :ind B respectively, are connected tothe ins'in's'f`- 1t is evident that my processisknoLhn t'- 85 ed to the particular`airangcmcnt illustrated in Figs, 1, 2, 3,4, 5 vmd 6 'or to' fth'e"number` of. cells, conditions -of,v 'T'volt'agg..gelte.;v A"described,` Whichare 'merely illustrativmfbutf' that my method may be prectisedxvithjsuc-, 90 cess under. varying conditionsgendf' -is'` :is`

broad as is yindicateur-by.the. aceompnying--j.'

claims. For example, '.conditions" vmayzbe ride the battery .into :folic eguali.

third of the clmrge,resiilting 'in'.` the coln-2 4plete charge of group B and the' txvothirds which completes the clisrgingofe these groups.

Or again it may 'bcadvisableto divide .the battery into. five eql`1al v groups," c. A, B, C, D and'E,' Whichgroups"maybo x charged three at a time's is illnstrnted'fn1115 Figs. .11, 12, 13,'14and 15.-v In this cas'ewef mav connect together'A, B vand C. inseries and giveone third of a chargc,.'then conn neet-B, Gand l) and give a one thirdcharge, then' C, D ."ind Eend give acharg of one 12o-2 third,resultingV in the`completc charge of group C, the two-thirds chrgiug of groups ;v Y D rindB 51nd theorie-third :harpgin{.,r of` AQ j Groups D, E nnd'A may then be' connected and j given a charge of oneA third 125 lcompletely chai-eilig E, A and B may then be connected :ind givena chai-geofonc-.thi-d. resulting'in the' complete charge;

I claim as new and desire to protect by Letters Patent is 1.-The method of charging a battery of secondary cells, which consists in dividing the battery into three groups connecting two of the groups in series, charging to one-half capacity, then connecting one of said groups and the third group in series, and charging until the said groups are fully charged and half charged respectively, and then connecting the two halfcharged groups in series and fully charging the same, substantially as described.

2. The method of charging a battery of secondary cells, from a source of maximum voltage less than that required to charge the cells when all are connected in series, which consists in dividing the battery into a plurality of groups, connecting together in series a plurality of groups such that the P. D. of the same on charge is less than the maximum voltage of the source, partly charging the same, connecting in series a second plurality of groups including one or more of said first groups, and having a P. D on charge less than the maximum voltage of the source, and giving the same a partial charge, and continuing to connect and charge groups not fully charged, in the same manner, until all are fully charged, substantially as described.

3. The method of charging a battery of secondary' cells, from a source of maximum voltage less than that required to charge the cells when all are connected in series, which consists in dividing the battery into a plurality of equal groups, connecting together in series a plurality of groups such that the voltage required to charge the same is slightly less than the maximum voltage of the source, partly charging the same, con-` necting 'in serles a second plurality of groups equal in number to the first, and including one or more of said first groups, and giving the same amount of charge as was given said first plurality, and continuing to connect and charge groups not fully charged, in the same manner, fully charged groups being omitted when new connections are made, until all are fully charged, the division of the groups and the length of charges being so calculated that all of the divisions of connected groups and all the lengths of charges may be equal, substantially as described.

4. The method of charging a battery of secondary cells, from a source of maximum voltage less than that required to charge the cells when all are connected in series, which consists in dividing the battery into a plurality of equal groups, connecting together certain groups in such a manner that the voltage required to charge the same is less than the maximum voltage of the source, charging the same partially at the same rate, changing the connections to form a new alinement of groups not fully charged and so connected that the voltage required to charge the same is less than the maximum voltage of the source, applying a charge to the same, and continuing to operate in the same manner until all the groups are fully charged, substantially as described.

This specification signed and witnessed this 3rd day of July, 191].

MILLER REESE HUTCHISON.

Witnesses:

HENRY LANAHAN, ANNA R. KLEHM. 

